<!DOCTYPE html>
<style>
div.five::before { content: '5: '; }
div.six::before { content: '6: '; }
div.seven::before { content: '7: '; }
</style>
<div>
    <div class='five'>Five</div>
    <div class='six'>Six</div>
    <div class='seven'>Seven</div>
</div>
</html>
